socket.c

   1 /*
   2  * Socket functions used in rsync.
   3  *
   4  * Copyright (C) 1992-2001 Andrew Tridgell <tridge@samba.org>
   5  * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
   6  * Copyright (C) 2003-2009 Wayne Davison
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, visit the http://fsf.org website.
  20  */
  21
  22 /* This file is now converted to use the new-style getaddrinfo()
  23  * interface, which supports IPv6 but is also supported on recent
  24  * IPv4-only machines.  On systems that don't have that interface, we
  25  * emulate it using the KAME implementation. */
  26
  27 #include "rsync.h"
  28 #include "itypes.h"
  29 #include <netinet/in_systm.h>
  30 #include <netinet/ip.h>
  31 #include <netinet/tcp.h>
  32
  33 extern char *bind_address;
  34 extern char *sockopts;
  35 extern int default_af_hint;
  36 extern int connect_timeout;
  37
  38 #ifdef HAVE_SIGACTION
  39 static struct sigaction sigact;
  40 #endif
  41
  42 static int sock_exec(const char *prog);
  43
  44 /* Establish a proxy connection on an open socket to a web proxy by using the
  45  * CONNECT method.  If proxy_user and proxy_pass are not NULL, they are used to
  46  * authenticate to the proxy using the "Basic" proxy-authorization protocol. */
  47 static int establish_proxy_connection(int fd, char *host, int port,
  48                                       char *proxy_user, char *proxy_pass)
  49 {
  50         char *cp, buffer[1024];
  51         char *authhdr, authbuf[1024];
  52         int len;
  53
  54         if (proxy_user && proxy_pass) {
  55                 stringjoin(buffer, sizeof buffer,
  56                          proxy_user, ":", proxy_pass, NULL);
  57                 len = strlen(buffer);
  58
  59                 if ((len*8 + 5) / 6 >= (int)sizeof authbuf - 3) {
  60                         rprintf(FERROR,
  61                                 "authentication information is too long\n");
  62                         return -1;
  63                 }
  64
  65                 base64_encode(buffer, len, authbuf, 1);
  66                 authhdr = "\r\nProxy-Authorization: Basic ";
  67         } else {
  68                 *authbuf = '\0';
  69                 authhdr = "";
  70         }
  71
  72         snprintf(buffer, sizeof buffer, "CONNECT %s:%d HTTP/1.0%s%s\r\n\r\n",
  73                  host, port, authhdr, authbuf);
  74         len = strlen(buffer);
  75         if (write(fd, buffer, len) != len) {
  76                 rsyserr(FERROR, errno, "failed to write to proxy");
  77                 return -1;
  78         }
  79
  80         for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
  81                 if (read(fd, cp, 1) != 1) {
  82                         rsyserr(FERROR, errno, "failed to read from proxy");
  83                         return -1;
  84                 }
  85                 if (*cp == '\n')
  86                         break;
  87         }
  88
  89         if (*cp != '\n')
  90                 cp++;
  91         *cp-- = '\0';
  92         if (*cp == '\r')
  93                 *cp = '\0';
  94         if (strncmp(buffer, "HTTP/", 5) != 0) {
  95                 rprintf(FERROR, "bad response from proxy -- %s\n",
  96                         buffer);
  97                 return -1;
  98         }
  99         for (cp = &buffer[5]; isDigit(cp) || *cp == '.'; cp++) {}
 100         while (*cp == ' ')
 101                 cp++;
 102         if (*cp != '2') {
 103                 rprintf(FERROR, "bad response from proxy -- %s\n",
 104                         buffer);
 105                 return -1;
 106         }
 107         /* throw away the rest of the HTTP header */
 108         while (1) {
 109                 for (cp = buffer; cp < &buffer[sizeof buffer - 1]; cp++) {
 110                         if (read(fd, cp, 1) != 1) {
 111                                 rsyserr(FERROR, errno,
 112                                         "failed to read from proxy");
 113                                 return -1;
 114                         }
 115                         if (*cp == '\n')
 116                                 break;
 117                 }
 118                 if (cp > buffer && *cp == '\n')
 119                         cp--;
 120                 if (cp == buffer && (*cp == '\n' || *cp == '\r'))
 121                         break;
 122         }
 123         return 0;
 124 }
 125
 126
 127 /* Try to set the local address for a newly-created socket.
 128  * Return -1 if this fails. */
 129 int try_bind_local(int s, int ai_family, int ai_socktype,
 130                    const char *bind_addr)
 131 {
 132         int error;
 133         struct addrinfo bhints, *bres_all, *r;
 134
 135         memset(&bhints, 0, sizeof bhints);
 136         bhints.ai_family = ai_family;
 137         bhints.ai_socktype = ai_socktype;
 138         bhints.ai_flags = AI_PASSIVE;
 139         if ((error = getaddrinfo(bind_addr, NULL, &bhints, &bres_all))) {
 140                 rprintf(FERROR, RSYNC_NAME ": getaddrinfo %s: %s\n",
 141                         bind_addr, gai_strerror(error));
 142                 return -1;
 143         }
 144
 145         for (r = bres_all; r; r = r->ai_next) {
 146                 if (bind(s, r->ai_addr, r->ai_addrlen) == -1)
 147                         continue;
 148                 freeaddrinfo(bres_all);
 149                 return s;
 150         }
 151
 152         /* no error message; there might be some problem that allows
 153          * creation of the socket but not binding, perhaps if the
 154          * machine has no ipv6 address of this name. */
 155         freeaddrinfo(bres_all);
 156         return -1;
 157 }
 158
 159 /* connect() timeout handler based on alarm() */
 160 static RETSIGTYPE contimeout_handler(UNUSED(int val))
 161 {
 162         connect_timeout = -1;
 163 }
 164
 165 /* Open a socket to a tcp remote host with the specified port.
 166  *
 167  * Based on code from Warren.  Proxy support by Stephen Rothwell.
 168  * getaddrinfo() rewrite contributed by KAME.net.
 169  *
 170  * Now that we support IPv6 we need to look up the remote machine's address
 171  * first, using af_hint to set a preference for the type of address.  Then
 172  * depending on whether it has v4 or v6 addresses we try to open a connection.
 173  *
 174  * The loop allows for machines with some addresses which may not be reachable,
 175  * perhaps because we can't e.g. route ipv6 to that network but we can get ip4
 176  * packets through.
 177  *
 178  * bind_addr: local address to use.  Normally NULL to bind the wildcard address.
 179  *
 180  * af_hint: address family, e.g. AF_INET or AF_INET6. */
 181 int open_socket_out(char *host, int port, const char *bind_addr,
 182                     int af_hint)
 183 {
 184         int type = SOCK_STREAM;
 185         int error, s;
 186         struct addrinfo hints, *res0, *res;
 187         char portbuf[10];
 188         char *h, *cp;
 189         int proxied = 0;
 190         char buffer[1024];
 191         char *proxy_user = NULL, *proxy_pass = NULL;
 192
 193         /* if we have a RSYNC_PROXY env variable then redirect our
 194          * connetcion via a web proxy at the given address. */
 195         h = getenv("RSYNC_PROXY");
 196         proxied = h != NULL && *h != '\0';
 197
 198         if (proxied) {
 199                 strlcpy(buffer, h, sizeof buffer);
 200
 201                 /* Is the USER:PASS@ prefix present? */
 202                 if ((cp = strrchr(buffer, '@')) != NULL) {
 203                         *cp++ = '\0';
 204                         /* The remainder is the HOST:PORT part. */
 205                         h = cp;
 206
 207                         if ((cp = strchr(buffer, ':')) == NULL) {
 208                                 rprintf(FERROR,
 209                                         "invalid proxy specification: should be USER:PASS@HOST:PORT\n");
 210                                 return -1;
 211                         }
 212                         *cp++ = '\0';
 213
 214                         proxy_user = buffer;
 215                         proxy_pass = cp;
 216                 } else {
 217                         /* The whole buffer is the HOST:PORT part. */
 218                         h = buffer;
 219                 }
 220
 221                 if ((cp = strchr(h, ':')) == NULL) {
 222                         rprintf(FERROR,
 223                                 "invalid proxy specification: should be HOST:PORT\n");
 224                         return -1;
 225                 }
 226                 *cp++ = '\0';
 227                 strlcpy(portbuf, cp, sizeof portbuf);
 228                 if (DEBUG_GTE(CONNECT, 1)) {
 229                         rprintf(FINFO, "connection via http proxy %s port %s\n",
 230                                 h, portbuf);
 231                 }
 232         } else {
 233                 snprintf(portbuf, sizeof portbuf, "%d", port);
 234                 h = host;
 235         }
 236
 237         memset(&hints, 0, sizeof hints);
 238         hints.ai_family = af_hint;
 239         hints.ai_socktype = type;
 240         error = getaddrinfo(h, portbuf, &hints, &res0);
 241         if (error) {
 242                 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: %s %s: %s\n",
 243                         h, portbuf, gai_strerror(error));
 244                 return -1;
 245         }
 246
 247         s = -1;
 248         /* Try to connect to all addresses for this machine until we get
 249          * through.  It might e.g. be multi-homed, or have both IPv4 and IPv6
 250          * addresses.  We need to create a socket for each record, since the
 251          * address record tells us what protocol to use to try to connect. */
 252         for (res = res0; res; res = res->ai_next) {
 253                 s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 254                 if (s < 0)
 255                         continue;
 256
 257                 if (bind_addr
 258                  && try_bind_local(s, res->ai_family, type,
 259                                    bind_addr) == -1) {
 260                         close(s);
 261                         s = -1;
 262                         continue;
 263                 }
 264                 if (connect_timeout > 0) {
 265                         SIGACTION(SIGALRM, contimeout_handler);
 266                         alarm(connect_timeout);
 267                 }
 268
 269                 set_socket_options(s, sockopts);
 270                 while (connect(s, res->ai_addr, res->ai_addrlen) < 0) {
 271                         if (connect_timeout < 0)
 272                                 exit_cleanup(RERR_CONTIMEOUT);
 273                         if (errno == EINTR)
 274                                 continue;
 275                         close(s);
 276                         s = -1;
 277                         break;
 278                 }
 279
 280                 if (connect_timeout > 0)
 281                         alarm(0);
 282
 283                 if (s < 0)
 284                         continue;
 285
 286                 if (proxied
 287                  && establish_proxy_connection(s, host, port,
 288                                                proxy_user, proxy_pass) != 0) {
 289                         close(s);
 290                         s = -1;
 291                         continue;
 292                 }
 293                 break;
 294         }
 295         freeaddrinfo(res0);
 296         if (s < 0) {
 297                 rsyserr(FERROR, errno, "failed to connect to %s", h);
 298                 return -1;
 299         }
 300         return s;
 301 }
 302
 303
 304 /* Open an outgoing socket, but allow for it to be intercepted by
 305  * $RSYNC_CONNECT_PROG, which will execute a program across a TCP
 306  * socketpair rather than really opening a socket.
 307  *
 308  * We use this primarily in testing to detect TCP flow bugs, but not
 309  * cause security problems by really opening remote connections.
 310  *
 311  * This is based on the Samba LIBSMB_PROG feature.
 312  *
 313  * bind_addr: local address to use.  Normally NULL to get the stack default. */
 314 int open_socket_out_wrapped(char *host, int port, const char *bind_addr,
 315                             int af_hint)
 316 {
 317         char *prog = getenv("RSYNC_CONNECT_PROG");
 318
 319         if (prog && strchr(prog, '%')) {
 320                 int hlen = strlen(host);
 321                 int len = strlen(prog) + 1;
 322                 char *f, *t;
 323                 for (f = prog; *f; f++) {
 324                         if (*f != '%')
 325                                 continue;
 326                         /* Compute more than enough room. */
 327                         if (f[1] == '%')
 328                                 f++;
 329                         else
 330                                 len += hlen;
 331                 }
 332                 f = prog;
 333                 if (!(prog = new_array(char, len)))
 334                         out_of_memory("open_socket_out_wrapped");
 335                 for (t = prog; *f; f++) {
 336                         if (*f == '%') {
 337                                 switch (*++f) {
 338                                 case '%':
 339                                         /* Just skips the extra '%'. */
 340                                         break;
 341                                 case 'H':
 342                                         memcpy(t, host, hlen);
 343                                         t += hlen;
 344                                         continue;
 345                                 default:
 346                                         f--; /* pass % through */
 347                                         break;
 348                                 }
 349                         }
 350                         *t++ = *f;
 351                 }
 352                 *t = '\0';
 353         }
 354
 355         if (DEBUG_GTE(CONNECT, 1)) {
 356                 rprintf(FINFO, "%sopening tcp connection to %s port %d\n",
 357                         prog ? "Using RSYNC_CONNECT_PROG instead of " : "",
 358                         host, port);
 359         }
 360         if (prog)
 361                 return sock_exec(prog);
 362         return open_socket_out(host, port, bind_addr, af_hint);
 363 }
 364
 365
 366 /* Open one or more sockets for incoming data using the specified type,
 367  * port, and address.
 368  *
 369  * The getaddrinfo() call may return several address results, e.g. for
 370  * the machine's IPv4 and IPv6 name.
 371  *
 372  * We return an array of file-descriptors to the sockets, with a trailing
 373  * -1 value to indicate the end of the list.
 374  *
 375  * bind_addr: local address to bind, or NULL to allow it to default. */
 376 static int *open_socket_in(int type, int port, const char *bind_addr,
 377                            int af_hint)
 378 {
 379         int one = 1;
 380         int s, *socks, maxs, i, ecnt;
 381         struct addrinfo hints, *all_ai, *resp;
 382         char portbuf[10], **errmsgs;
 383         int error;
 384
 385         memset(&hints, 0, sizeof hints);
 386         hints.ai_family = af_hint;
 387         hints.ai_socktype = type;
 388         hints.ai_flags = AI_PASSIVE;
 389         snprintf(portbuf, sizeof portbuf, "%d", port);
 390         error = getaddrinfo(bind_addr, portbuf, &hints, &all_ai);
 391         if (error) {
 392                 rprintf(FERROR, RSYNC_NAME ": getaddrinfo: bind address %s: %s\n",
 393                         bind_addr, gai_strerror(error));
 394                 return NULL;
 395         }
 396
 397         /* Count max number of sockets we might open. */
 398         for (maxs = 0, resp = all_ai; resp; resp = resp->ai_next, maxs++) {}
 399
 400         socks = new_array(int, maxs + 1);
 401         errmsgs = new_array(char *, maxs);
 402         if (!socks || !errmsgs)
 403                 out_of_memory("open_socket_in");
 404
 405         /* We may not be able to create the socket, if for example the
 406          * machine knows about IPv6 in the C library, but not in the
 407          * kernel. */
 408         for (resp = all_ai, i = ecnt = 0; resp; resp = resp->ai_next) {
 409                 s = socket(resp->ai_family, resp->ai_socktype,
 410                            resp->ai_protocol);
 411
 412                 if (s == -1) {
 413                         int r = asprintf(&errmsgs[ecnt++],
 414                                 "socket(%d,%d,%d) failed: %s\n",
 415                                 (int)resp->ai_family, (int)resp->ai_socktype,
 416                                 (int)resp->ai_protocol, strerror(errno));
 417                         if (r < 0)
 418                                 out_of_memory("open_socket_in");
 419                         /* See if there's another address that will work... */
 420                         continue;
 421                 }
 422
 423                 setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
 424                            (char *)&one, sizeof one);
 425                 if (sockopts)
 426                         set_socket_options(s, sockopts);
 427                 else
 428                         set_socket_options(s, lp_socket_options());
 429
 430 #ifdef IPV6_V6ONLY
 431                 if (resp->ai_family == AF_INET6) {
 432                         if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
 433                                        (char *)&one, sizeof one) < 0
 434                             && default_af_hint != AF_INET6) {
 435                                 close(s);
 436                                 continue;
 437                         }
 438                 }
 439 #endif
 440
 441                 /* Now we've got a socket - we need to bind it. */
 442                 if (bind(s, resp->ai_addr, resp->ai_addrlen) < 0) {
 443                         /* Nope, try another */
 444                         int r = asprintf(&errmsgs[ecnt++],
 445                                 "bind() failed: %s (address-family %d)\n",
 446                                 strerror(errno), (int)resp->ai_family);
 447                         if (r < 0)
 448                                 out_of_memory("open_socket_in");
 449                         close(s);
 450                         continue;
 451                 }
 452
 453                 socks[i++] = s;
 454         }
 455         socks[i] = -1;
 456
 457         if (all_ai)
 458                 freeaddrinfo(all_ai);
 459
 460         /* Only output the socket()/bind() messages if we were totally
 461          * unsuccessful, or if the daemon is being run with -vv. */
 462         for (s = 0; s < ecnt; s++) {
 463                 if (!i || DEBUG_GTE(BIND, 1))
 464                         rwrite(FLOG, errmsgs[s], strlen(errmsgs[s]), 0);
 465                 free(errmsgs[s]);
 466         }
 467         free(errmsgs);
 468
 469         if (!i) {
 470                 rprintf(FERROR,
 471                         "unable to bind any inbound sockets on port %d\n",
 472                         port);
 473                 free(socks);
 474                 return NULL;
 475         }
 476         return socks;
 477 }
 478
 479
 480 /* Determine if a file descriptor is in fact a socket. */
 481 int is_a_socket(int fd)
 482 {
 483         int v;
 484         socklen_t l = sizeof (int);
 485
 486         /* Parameters to getsockopt, setsockopt etc are very
 487          * unstandardized across platforms, so don't be surprised if
 488          * there are compiler warnings on e.g. SCO OpenSwerver or AIX.
 489          * It seems they all eventually get the right idea.
 490          *
 491          * Debian says: ``The fifth argument of getsockopt and
 492          * setsockopt is in reality an int [*] (and this is what BSD
 493          * 4.* and libc4 and libc5 have).  Some POSIX confusion
 494          * resulted in the present socklen_t.  The draft standard has
 495          * not been adopted yet, but glibc2 already follows it and
 496          * also has socklen_t [*]. See also accept(2).''
 497          *
 498          * We now return to your regularly scheduled programming.  */
 499         return getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0;
 500 }
 501
 502
 503 static RETSIGTYPE sigchld_handler(UNUSED(int val))
 504 {
 505 #ifdef WNOHANG
 506         while (waitpid(-1, NULL, WNOHANG) > 0) {}
 507 #endif
 508 #ifndef HAVE_SIGACTION
 509         signal(SIGCHLD, sigchld_handler);
 510 #endif
 511 }
 512
 513
 514 void start_accept_loop(int port, int (*fn)(int, int))
 515 {
 516         fd_set deffds;
 517         int *sp, maxfd, i;
 518
 519 #ifdef HAVE_SIGACTION
 520         sigact.sa_flags = SA_NOCLDSTOP;
 521 #endif
 522
 523         /* open an incoming socket */
 524         sp = open_socket_in(SOCK_STREAM, port, bind_address, default_af_hint);
 525         if (sp == NULL)
 526                 exit_cleanup(RERR_SOCKETIO);
 527
 528         /* ready to listen */
 529         FD_ZERO(&deffds);
 530         for (i = 0, maxfd = -1; sp[i] >= 0; i++) {
 531                 if (listen(sp[i], 5) < 0) {
 532                         rsyserr(FERROR, errno, "listen() on socket failed");
 533 #ifdef INET6
 534                         if (errno == EADDRINUSE && i > 0) {
 535                                 rprintf(FINFO,
 536                                     "Try using --ipv4 or --ipv6 to avoid this listen() error.\n");
 537                         }
 538 #endif
 539                         exit_cleanup(RERR_SOCKETIO);
 540                 }
 541                 FD_SET(sp[i], &deffds);
 542                 if (maxfd < sp[i])
 543                         maxfd = sp[i];
 544         }
 545
 546         /* now accept incoming connections - forking a new process
 547          * for each incoming connection */
 548         while (1) {
 549                 fd_set fds;
 550                 pid_t pid;
 551                 int fd;
 552                 struct sockaddr_storage addr;
 553                 socklen_t addrlen = sizeof addr;
 554
 555                 /* close log file before the potentially very long select so
 556                  * file can be trimmed by another process instead of growing
 557                  * forever */
 558                 logfile_close();
 559
 560 #ifdef FD_COPY
 561                 FD_COPY(&deffds, &fds);
 562 #else
 563                 fds = deffds;
 564 #endif
 565
 566                 if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 1)
 567                         continue;
 568
 569                 for (i = 0, fd = -1; sp[i] >= 0; i++) {
 570                         if (FD_ISSET(sp[i], &fds)) {
 571                                 fd = accept(sp[i], (struct sockaddr *)&addr,
 572                                             &addrlen);
 573                                 break;
 574                         }
 575                 }
 576
 577                 if (fd < 0)
 578                         continue;
 579
 580                 SIGACTION(SIGCHLD, sigchld_handler);
 581
 582                 if ((pid = fork()) == 0) {
 583                         int ret;
 584                         for (i = 0; sp[i] >= 0; i++)
 585                                 close(sp[i]);
 586                         /* Re-open log file in child before possibly giving
 587                          * up privileges (see logfile_close() above). */
 588                         logfile_reopen();
 589                         ret = fn(fd, fd);
 590                         close_all();
 591                         _exit(ret);
 592                 } else if (pid < 0) {
 593                         rsyserr(FERROR, errno,
 594                                 "could not create child server process");
 595                         close(fd);
 596                         /* This might have happened because we're
 597                          * overloaded.  Sleep briefly before trying to
 598                          * accept again. */
 599                         sleep(2);
 600                 } else {
 601                         /* Parent doesn't need this fd anymore. */
 602                         close(fd);
 603                 }
 604         }
 605 }
 606
 607
 608 enum SOCK_OPT_TYPES {OPT_BOOL,OPT_INT,OPT_ON};
 609
 610 struct
 611 {
 612   char *name;
 613   int level;
 614   int option;
 615   int value;
 616   int opttype;
 617 } socket_options[] = {
 618   {"SO_KEEPALIVE",      SOL_SOCKET,    SO_KEEPALIVE,    0,                 OPT_BOOL},
 619   {"SO_REUSEADDR",      SOL_SOCKET,    SO_REUSEADDR,    0,                 OPT_BOOL},
 620   {"SO_BROADCAST",      SOL_SOCKET,    SO_BROADCAST,    0,                 OPT_BOOL},
 621 #ifdef TCP_NODELAY
 622   {"TCP_NODELAY",       IPPROTO_TCP,   TCP_NODELAY,     0,                 OPT_BOOL},
 623 #endif
 624 #ifdef IPTOS_LOWDELAY
 625   {"IPTOS_LOWDELAY",    IPPROTO_IP,    IP_TOS,          IPTOS_LOWDELAY,    OPT_ON},
 626 #endif
 627 #ifdef IPTOS_THROUGHPUT
 628   {"IPTOS_THROUGHPUT",  IPPROTO_IP,    IP_TOS,          IPTOS_THROUGHPUT,  OPT_ON},
 629 #endif
 630 #ifdef SO_SNDBUF
 631   {"SO_SNDBUF",         SOL_SOCKET,    SO_SNDBUF,       0,                 OPT_INT},
 632 #endif
 633 #ifdef SO_RCVBUF
 634   {"SO_RCVBUF",         SOL_SOCKET,    SO_RCVBUF,       0,                 OPT_INT},
 635 #endif
 636 #ifdef SO_SNDLOWAT
 637   {"SO_SNDLOWAT",       SOL_SOCKET,    SO_SNDLOWAT,     0,                 OPT_INT},
 638 #endif
 639 #ifdef SO_RCVLOWAT
 640   {"SO_RCVLOWAT",       SOL_SOCKET,    SO_RCVLOWAT,     0,                 OPT_INT},
 641 #endif
 642 #ifdef SO_SNDTIMEO
 643   {"SO_SNDTIMEO",       SOL_SOCKET,    SO_SNDTIMEO,     0,                 OPT_INT},
 644 #endif
 645 #ifdef SO_RCVTIMEO
 646   {"SO_RCVTIMEO",       SOL_SOCKET,    SO_RCVTIMEO,     0,                 OPT_INT},
 647 #endif
 648   {NULL,0,0,0,0}
 649 };
 650
 651
 652 /* Set user socket options. */
 653 void set_socket_options(int fd, char *options)
 654 {
 655         char *tok;
 656
 657         if (!options || !*options)
 658                 return;
 659
 660         options = strdup(options);
 661
 662         if (!options)
 663                 out_of_memory("set_socket_options");
 664
 665         for (tok = strtok(options, " \t,"); tok; tok = strtok(NULL," \t,")) {
 666                 int ret=0,i;
 667                 int value = 1;
 668                 char *p;
 669                 int got_value = 0;
 670
 671                 if ((p = strchr(tok,'='))) {
 672                         *p = 0;
 673                         value = atoi(p+1);
 674                         got_value = 1;
 675                 }
 676
 677                 for (i = 0; socket_options[i].name; i++) {
 678                         if (strcmp(socket_options[i].name,tok)==0)
 679                                 break;
 680                 }
 681
 682                 if (!socket_options[i].name) {
 683                         rprintf(FERROR,"Unknown socket option %s\n",tok);
 684                         continue;
 685                 }
 686
 687                 switch (socket_options[i].opttype) {
 688                 case OPT_BOOL:
 689                 case OPT_INT:
 690                         ret = setsockopt(fd,socket_options[i].level,
 691                                          socket_options[i].option,
 692                                          (char *)&value, sizeof (int));
 693                         break;
 694
 695                 case OPT_ON:
 696                         if (got_value)
 697                                 rprintf(FERROR,"syntax error -- %s does not take a value\n",tok);
 698
 699                         {
 700                                 int on = socket_options[i].value;
 701                                 ret = setsockopt(fd,socket_options[i].level,
 702                                                  socket_options[i].option,
 703                                                  (char *)&on, sizeof (int));
 704                         }
 705                         break;
 706                 }
 707
 708                 if (ret != 0) {
 709                         rsyserr(FERROR, errno,
 710                                 "failed to set socket option %s", tok);
 711                 }
 712         }
 713
 714         free(options);
 715 }
 716
 717
 718 /* This is like socketpair but uses tcp.  The function guarantees that nobody
 719  * else can attach to the socket, or if they do that this function fails and
 720  * the socket gets closed.  Returns 0 on success, -1 on failure.  The resulting
 721  * file descriptors are symmetrical.  Currently only for RSYNC_CONNECT_PROG. */
 722 static int socketpair_tcp(int fd[2])
 723 {
 724         int listener;
 725         struct sockaddr_in sock;
 726         struct sockaddr_in sock2;
 727         socklen_t socklen = sizeof sock;
 728         int connect_done = 0;
 729
 730         fd[0] = fd[1] = listener = -1;
 731
 732         memset(&sock, 0, sizeof sock);
 733
 734         if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
 735                 goto failed;
 736
 737         memset(&sock2, 0, sizeof sock2);
 738 #ifdef HAVE_SOCKADDR_IN_LEN
 739         sock2.sin_len = sizeof sock2;
 740 #endif
 741         sock2.sin_family = PF_INET;
 742         sock2.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 743
 744         if (bind(listener, (struct sockaddr *)&sock2, sizeof sock2) != 0
 745          || listen(listener, 1) != 0
 746          || getsockname(listener, (struct sockaddr *)&sock, &socklen) != 0
 747          || (fd[1] = socket(PF_INET, SOCK_STREAM, 0)) == -1)
 748                 goto failed;
 749
 750         set_nonblocking(fd[1]);
 751
 752         sock.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 753
 754         if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) == -1) {
 755                 if (errno != EINPROGRESS)
 756                         goto failed;
 757         } else
 758                 connect_done = 1;
 759
 760         if ((fd[0] = accept(listener, (struct sockaddr *)&sock2, &socklen)) == -1)
 761                 goto failed;
 762
 763         close(listener);
 764         listener = -1;
 765
 766         set_blocking(fd[1]);
 767
 768         if (connect_done == 0) {
 769                 if (connect(fd[1], (struct sockaddr *)&sock, sizeof sock) != 0
 770                     && errno != EISCONN)
 771                         goto failed;
 772         }
 773
 774         /* all OK! */
 775         return 0;
 776
 777  failed:
 778         if (fd[0] != -1)
 779                 close(fd[0]);
 780         if (fd[1] != -1)
 781                 close(fd[1]);
 782         if (listener != -1)
 783                 close(listener);
 784         return -1;
 785 }
 786
 787
 788 /* Run a program on a local tcp socket, so that we can talk to it's stdin and
 789  * stdout.  This is used to fake a connection to a daemon for testing -- not
 790  * for the normal case of running SSH.
 791  *
 792  * Retruns a socket which is attached to a subprocess running "prog". stdin and
 793  * stdout are attached. stderr is left attached to the original stderr. */
 794 static int sock_exec(const char *prog)
 795 {
 796         pid_t pid;
 797         int fd[2];
 798
 799         if (socketpair_tcp(fd) != 0) {
 800                 rsyserr(FERROR, errno, "socketpair_tcp failed");
 801                 return -1;
 802         }
 803         if (DEBUG_GTE(CMD, 1))
 804                 rprintf(FINFO, "Running socket program: \"%s\"\n", prog);
 805
 806         pid = fork();
 807         if (pid < 0) {
 808                 rsyserr(FERROR, errno, "fork");
 809                 exit_cleanup(RERR_IPC);
 810         }
 811
 812         if (pid == 0) {
 813                 close(fd[0]);
 814                 if (dup2(fd[1], STDIN_FILENO) < 0
 815                  || dup2(fd[1], STDOUT_FILENO) < 0) {
 816                         fprintf(stderr, "Failed to run \"%s\"\n", prog);
 817                         exit(1);
 818                 }
 819                 exit(system(prog));
 820         }
 821
 822         close(fd[1]);
 823         return fd[0];
 824 }